Efficient Synthesis of Biaryl‐Bridged Seven‐Membered Lactones via <i>N</i>‐Heterocyclic Carbene Catalyzed Dynamic Kinetic Resolution
Huan Gong, Han Zhuang, Yang Xiao, Yao Chen, Xiaoqing Lai, Zhuofeng Deng, Jianing An, Yiqun Li, Jianfeng Xu, Xingkuan Chen
Abstract
Comprehensive Summary Bridged biaryl atropisomers are widely recognized as a significant structural motif commonly found in bioactive molecules and natural products. Herein, we report an organocatalytic dynamic kinetic resolution (DKR) approach for the synthesis of optically pure biaryl‐bridged seven‐membered lactones. In the presence of a chiral N ‐heterocyclic carbene (NHC) catalyst, racemic biaryl‐bridged hemiacetals, generated in situ from 2’‐formyl‐2‐biphenyl carboxylic acids, undergo stereoselective coupling with NHC‐bound acylazolium intermediates derived from NHC and aldehydes. This transformation delivers seven‐membered biaryl‐bridged lactone products with very high yields and good to excellent regio‐ and enantioselectivities.